As of mid 2015, SamCart has had a direct integration to OptimizeMember. We created a blog post to give an overview of how to integrate.
http://www.optimizepress.com/how-to-use-samcart-with-optimizemember-for-your-membership-site/
If you have any trouble with this integration, we would suggest making sure your site has PHP 5.6 or higher. Any further issues should be brought up with your web host or SamCart (as they are the ones who built this integration from their end).
In most cases we find that either the web host is blocking SamCart’s integration IP address, or the PHP version is not allowing remote communications.
NOTE: We would suggest a minimum of PHP 5.6 for integrating with SamCart. We have had some reports of the integration not working, and upgrading to PHP 5.6 solved the issue. It is possible that some older versions of PHP may not be trusted as much by your web host (since they are very outdated), so upgrading will help ensure a smoother integration process.
If you need further help or have any questions about how to do this please send us a message by clicking the link below.